Optical disk player

ABSTRACT

In an optical disk player according to this invention, a movable chassis mounted with an optical pickup, a turntable and the like is supported by springs joined with respective positions of a frame, and in this optical disk player, dampers are inserted between the frame and the movable chassis to absorb the energy of vibrations of the movable chassis. At the same time, a correcting means such as a coiled spring is so arranged as to be capable of changing the biasing force for biasing the movable chassis in a neutral condition with respect to the frame by adjustment operation. With the above arrangement, the slope of Q-value of the resonance region becomes moderate enough at the leading edge of the slope, and thus the vibration isolation characteristic is improved, so that sound omissions tend not to occur. The degradation of the vibration isolation characteristic of the damper that usually occurs on tilt of the chassis is effectively prevented. At the same time, a collision between the frame and the movable chassis can be prevented without increasing the movable range of the movable chassis with respect to the frame.

TECHNICAL FIELD

The present invention relates to an optical disk player having animproved vibration isolation characteristic and suitable for use in amoving object, such as an automobile, an aircraft or the like.

BACKGROUND ART

In the conventional cassette tape player for cars using magnetic tapes,no vibration isolation mechanism has been substantially providedalthough the performance of the player falls due to wow and fluttercaused by the vibration of the car, because the degradation of theperformance is not reagarded as very serious problem.

However, when an optical disk player for scanning and reproducinghigh-density signals recorded on a disk by the use of an optical pickupis mounted in the moving object, such as the automobile, the aircraft orthe like, sound omissions tend to occur due to vibrations of the movingobject. Therefore, the principal part of the player is placed on aplayer frame through rubber cushions so as to be insulated from thevibration. But quality factor Q of the resonance region of the vibrationgenerated in the principal part of the player tends to be inevitablylarge, so that it is often difficult to have the player operatednormally. In addition, the frequency band of the vibrations caused undervarious severe conditions with which the car is met, normally includesthe above resonance region.

Therefore, if the optical disk player for cars is isolated from thevibrations only by rubber cushions, sound omissions occur, and itbecomes difficult to enable the optical disk player to be normallyoperated.

Hence, the following mechanism is proposed as the vibration isolationmechanism of the optical disk player for cars instead of rubbercushions. In the mechanism, a movable chassis (on which an opticalpick-up, a turntable and the like are mounted) is suspended bysuspension coiled springs in several positions of a frame such as astationary chassis or a cabinet, and dampers which prevent the movablechassis from vibrating are inserted between the frame and the movablechassis so that the movable chassis can be floated with respect to theframe. Thus, resonance frequency f_(O) in the lateral (horizontal)direction of the vibration system is decreased. Hence, by adoption ofthe above vibration isolation mechanisum, the slope of Q-value of theresonance region becomes moderate enough at the leading edge of theslope in comparison with the case in which the rubber cushion isadopted, so that the noted sound omission does not occur, and thevibration isolation characteristic is greatly improved.

However, if the optical disk player having the vibration isolationmechanism as described above is mounted on the car, the followingfurther trouble arises.

When the frame is mounted in the player mounting position of the car ata given angle with the horizontal plane of the car, the direction of thegravity acting on the movable chassis changes, so that the movablechassis tends to be displaced from a neutral equilibrium position withrespect to the frame.

The movable chassis is displaced from the neutral equilibrium positionwith respect to the frame until the dampers are elastically deformed tore-establish an equilibrium state. Thereby, the vibration isolationcharacteristic of the damper is degraded. In addition, as the movablechassis deviates from the neutral equilibrium position with respect tothe frame, the distance between the movable chassis and the frame in thedisplacement direction of the movable chassis is decreased, so that themovable range in the displacement direction of the movable chassis isdecreased with respect to the frame.

DISCLOSURE OF INVENTION

In order to solve the above problems, there is disclosed an optical diskplayer of the present invention, in which a movable chassis is mountedwith an optical pickup, a turntable and the like, and so supported bycoiled springs joined with a frame in several positions as to be floatedwith, respect to the player. The optical disk player frame furthercomprises dampers inserted between the frame and the movable chassis toabsorb the energy of vibrations of the movable chassis, and biasingmeans for correction capable of varying a biasing force to enable themovable chassis to be biased with respect to the frame by adjustmentoperation, and also inserted between the frame and the movable chassis,whereby the positional deviation of the movable chassis due to thesetting angle of the frame from a neutral equilibrium position withrespect to the frame is corrected by changing the biasing force byadjustment operation, and the movable chassis is kept in the neutralequilibrium position regardless of the setting angle.

With the above arrangement, the increase in Q-value of the resonanceregion can be prevented, so that the vibration isolation characteristicsare improved and sound omissions tend not to occur. The degradation ofthe vibration isolation characteristic of the damper can be effectivelyprevented, and at the same time, a collision between the frame and themovable chassis can be prevented without increasing the movable range ofthe movable chassis with respect to the frame.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic perspective view showing a chassis and a frame inan embodiment of an optical disk player for cars to which the presentinvention is applied;

FIG. 2 is a front view of the chassis and frame in FIG. 1 taken alongthe line II--II thereof;

FIG. 3 is a sectional view of the player in FIG. 1 taken along the lineIII--III thereof;

FIG. 4 is a perspective view showing the overall arrangement of theoptical disk player in FIG. 1;

FIG. 5 is a perspective view of a damper in FIG. 1 in an enlarged andexploded state;

FIG. 6A is a longitudinal sectional view of the damper in FIG. 1 in theneutral equilibrium state;

FIG. 6B is a sectional view of the damper taken along the line VIB--VIBin FIG. 6A;

FIG. 6C is a longitudinal sectional view similar to FIG. 6A and showinga state wherein the damper is displaced from the neutral equilibriumposition in the direction perpendicular to an axis thereof;

FIG. 6D is a longitudinal sectional view similar to FIG. 6A and showinga state wherein the damper is displaced from the neutral equilibriumposition in the axial direction thereof;

FIG. 7 is an enlarged plan view of a mounting state correction mechanismshown in FIG. 1;

FIG. 8 is a sectional view of the mounting state correction mechanismtaken along the line VIII--VIII in FIG. 7;

FIG. 9 is an exploded perspective view of the mounting state correctionmechanism shown in FIG. 7;

FIG. 10 is a view similar to FIG. 3, showing a state wherein the opticaldisk player is mounted in a player mounting position of a car at a givenangle with the horizontal plane of the car under a condition that thecoiled spring for correction is not adjusted;

FIG. 11 is a view similar to FIG. 10, showing a state wherein theoptical disk player is mounted in the player mounting position after thecoiled spring for correction is adjusted;

FIG. 12 is a view similar to FIG. 7, showing another embodiment of themounting state correction mechanism; and

FIG. 13 is a sectional view of the mounting state correction mechanismin FIG. 12 taken along the line XIII--XIII thereof.

BEST MODE OF CARRYING OUT THE INVENTION

An embodiment in which the present invention is applied to an opticaldisk player for cars will be described with reference to theaccompanying drawings. FIGS. 1 to 11 show the embodiment and firstly, astate of a principal part 2 of the player mounted on a frame 1, that is,a stationary chassis will be described with reference to FIGS. 1 to 3.

The principal part 2 of the player comprises a movable chassis 2a, anoptical pickup 6 which is movable along a guide groove (not shown)formed in the movable chassis 2a, and a turntable 3a on which an opticaldisk (not shown) as a recording medium is to be placed. On the movablechassis 2a, there are also mounted a motor 3 and the like. The disk (notshown) is turned by the turntable 3a driven by the motor 3. The diskinserted in the direction of arrow A in FIG. 1 is chucked by a diskchuck 4 rotatably mounted on the free end of a chucking arm 5 which isvertically swingable.

The frame 1 accommodated in a cabinet 30 (see FIG. 4) and mounted in aplayer mounting position (not shown) of the car comprises a pair of sideplates 7 and a connecting member 8 which connects the side plates 7 witheach other. The movable chassis 2a is suspended from the frame 1 throughfour suspension coiled springs 10. Four dampers 11 are inserted betweenthe movable chassis 2a and the side plates 7 of the frame 1 near therespective suspension coiled springs 10 so as to absorb the energy ofvibrations of the principal part 2 of the player. Therefore, theprincipal part 2 of the player is kept in a floating state with respectto the frame 1.

A mounting state correction mechanism 12 is disposed between theconnecting member 8 of the frame 1 and an upper plate 9 of the movablechassis 2a so as to change an equilibrium position of the principal part2 of the player with respect to the frame 1 when the frame 1 is sosecured as to have a given angle with the horizontal plane H of the car(see FIGS. 10 and 11). The mounting state correction mechanism 12 willbe described later with reference to FIGS. 7 and 8.

Accommodated in the cabinet 30 shown in FIG. 4 is the frame 1 to whichthe principal part 2 of the player and the like are secured as shown inFIG. 1. When a lid 31 is swung on a screw 32, with which the lid 31 isattached to the upper wall of the cabinet 30, an adjustment-operationopening 33 formed in the upper wall of the cabinet 30 is opened orclosed, so that an eccentric cam 18 of the mcunting state correctionmechanism 12 can be turned with a screw-driver (not shown) insertedthrough the opening 33.

The constitution and function of the damper 11 will be described withreference to FIGS. 5 to 6D.

The damper 11 comprises a vessel 11a mounted on the side plate 7 of theframe 1, and a rod 11b fixedly fitted in a mounting hole 45 of themovable chassis 2a.

The vessel 11a is made of an elastic material such as rubber and definesa space 40 in which a viscous fluid is sealed. A movable member 41 is sodisposed as to project into the substantially central portion of thespace 40. The movable member 41 is of a quadrangular prism, on the outerperiphery of which projections 42 are disposed so as to increase viscousdrag of the movable member 41 in the viscous fluid, and into a hole 43forming the inner periphery of which the rod 11b is press-fitted. Thespace 40 is defined by four walls which are in opposed relation to theouter periphery of the movable member 41, so that the space 40 has asubstantially square cross-secton. The rod 11b may comprise a rod bodywith a cylindrical body of rubber mounted on the rod body.

The vessel 11a has a lid 48 at the outer side thereof and a stopper 44of a thick ring-like flange at the inner side thereof. Between themovable member 41 and the stopper 44, there is disposed a film-likeconnecting member 49 which protrudes more than the stopper 44 like adonut. Between the stopper 44 and the connecting member 49, there is ananuular groove 50 of a substantially triangular shape in section, thewidth of which gradually decreases towards its bottom. A groove 46 isformed in the outer periphery of the stopper 44 and is engaged with therim of a hole 28 formed in the side plate 7 of the frame 1. A pair ofprojections 47 formed in the groove 46 are engaged with recesses (notshown) formed in the rim of the hole 28 in order to determine thesetting angle of the vessel 11a in the side plate 7.

In this embodiment, silicone oil (12,000 cS) fills the space 40 formedin the body of the vessel 11a made of butyl rubber, and then the lid 48of butyl rubber is attached to the vessel body so as to enclose the oil.The vessel 11a is mounted in the side plate 7 of the frame 1 in such away that the pair of projections 47 of the vessel 11a are aligned witheach other along the horizontal line.

If the frame 1 is vertically moved, for example, moved downward withrespect to the movable chassis 2a, the vessel 11a is also moveddownward, that is, in a direction perpendicular to the axial directionthereof as shown in FIG. 6C, and the rod 11b fixedly fitted in themounting hole 45 of the movable chassis 2a is also to be moved downwardtogether with the vessel 11a, but due to elastic deformation of theconnecting member 49 made of the film, the rod 11b with the movablemember 41 is relatively moved in the space 40 in three dimensionaldirection. In other words, the rod 11b is not substantially moved and asshown in FIG. 6C, the vessel 11a is so deformed as to move downward onlythe outer portion of the vessel 11a, such as the stopper 44 and thelike. Therefore, the viscous drag is generated between the silicone oiland the movable member 41 since the silicone oil in the vessel 11a ismoved from the lower position to the upper position of the movablemember 41, so that the movable chassis 2a is prevented from assuming thevibration of the frame 1, because the energy of the vibration isabsorbed by the viscous drag.

When the frame 1 vibrates in the back-and-forth direction (in theright-and-left direction in FIG. 3) with respect to the movable chassis2a, the vessel 11a is deformed in a similar way as indicated in FIG. 6C.The Vibration from the frame 1 to the movable chassis 2a is sufficientlyattenuated as the vertical vibration is.

If the frame 1 vibrates in the right-and-left direction in FIG. 2 withrespect to the movable chassis 2a, the vessel 11a is so moved as toapproach the movable chassis 2a as indicated in FIG. 6D, so that thevibration from the frame 1 to the movable chassis 2a is sufficientlyattenuated due to the deformation of the vessel 11a shown in FIG. 6D,and the same may be said of the vessel 11a moved away from the movablechassis 2a.

The stopper 44 and lid 48 of the vessel 11a function as stoppers andimpact absorbers when the vessel 11a is overrun in the axial directionof the damper 11 due to the vibration of the frame 1. That is, when thestopper 44 of the vessel 11a comes closer to the movable chassis 2a fromthe state shown in FIG. 6D, the movable chassis 2a is elasticallybrought into contact with the side surface of the stopper 44. At thesame time, the flat distal end of the movable member 41 is elasticallybrought into contact with the inner side of the lid 48. Therefore, theimpact energy can be absorbed and further movement of the frame 7 towardthe movable chassis 2a can be prevented.

The projections 42 of the movable member 41 function as stoppers andimpact absorbers when the frame 1 vibrates in the vertical orback-and-forth direction thereof with respect to the movable chassis 2a.That is, as indicated in chain-dotted lines in FIG. 6B, when the movablemember 41 vibrates and relatively comes close to the upper wall of thespace 40, the upper projection 42 is elastically brought into contactwith the upper wall. As a result, the impact energy can be absorbed, andfurther displacement of the rod 11b relative to the vessel 11a can beprevented.

Differing from the conventional damper whose vessel has two spaces, thevessel 11a of the damper 11 comprises only one space 40 as mentionedabove, and the vibration energy is dissipated due to the movement of themovable member 41 against the viscous fluid in the space 40. As theprojection 42 protrudes from each of the four outer surfaces of themovable member 41 of the quadrangular prism, the surface of the movablemember 41 is uneven, so that the energy dissipation due to the movementof the movable member 41 becomes larger, because the surface area of themovable member 41 immersed in the viscous fluid is effectivelyincreased. Furthermore, since the vessel 11a is made of the butylrubber, the vessel 11a deforms repeatedly as the frame 1 vibrates withrespect to the movable chassis 2a, so that the vibration energy isdissipated in the butyl rubber. Therefore, the vessel 11a, in otherwords, the damper 11, has a large energy absorbing capacity although itis rather small.

As shown in FIGS. 7 to 9, the mounting state correction mechanism 12comprises a rectangular frame 13, two pairs of guide hooks 14 formed onthe connecting member 8 of the frame 1 in order to have the rectangularframe 13 slid along the guide hooks 14, an eccentric cam 18 for causingthe rectangular frame 13 to be slid along the guide hooks 14, and acoiled spring 17 which joins engaging holes 16 and 15, respectivelyformed in the rectangular frame 13 and the upper plate 9 of the movablechassis 2a. The coiled spring 17 can give a biasing force apredetermined magnitude to the movable chassis 2a so as to correct apositional deviation of the movable chassis 2a from the neutralequilibrium position with respect to the frame 1 when the frame 1 ismounted at a given angle with the horizontal plane. However, the coiledspring 17 has such a low spring constant as it scarcely gives anyinfluence to the vibration system which comprises the frame 1, theprincipal part 2 of the player, the suspension coiled springs 10 and thedampers 11, (whose frequency f₀ in the lateral (horizontal) direction isgenerally low).

The mounting state correction mechanism 12 is so arranged between theframe 1 and the movable chassis 2a as to have its central line, by whichthe mechanism 12 is symmetrically bisected in right and left portions,substantially included in the perpendicular plane including the centerof gravity G of the principal part 2 of the player. The direction of thebiasing force of the coiled spring 17 acting on the movable chassis 2ais always within the perpendicular plane, and the positional deviationof the movable chassis 2a from the neutral equilibrium position withrespect to the frame 1 is substantially kept in parallel with theperpendicular plane. In this embodiment, the coiled spring 17 isarranged at an angle of about 10° with the bottom surface of the movablechassis 2a, which is the reference surface of the principal part 2 ofthe player, when the principal part 2 of the player is held in theneutral equilibrium position.

Formed in the head of the eccentric cam 18 is a notch which is to beengaged with the screwdriver. A screw hole 20 is formed in the bottom ofthe eccentric cam 18. A locking projection 21 is formed near the outeredge of the bottom surface. As is apparent from FIG. 9, the eccentriccam 18 is secured with a screw 24, on which a washer 23 and a biasingspring 22 are mounted. Thus, the eccentric cam 18 is pressed against theconnecting member 8 with the biasing spring 22, so that the lockingprojection 21 of the eccentric cam 18 is selectively engaged with one ofa plurality of radial grooves formed around a hole 25 formed in theframe 1. Therefore, the eccentric cam 18 is held at a desired adjustedangular position.

The function of the mounting state correction mechanism 12 at the timewhen the frame 1 is mounted in the player mounting position of the carin parallel with, or at a given angle with the horizontal plane H of thecar, will be described with reference to FIGS. 3, 10, and 11.

When the frame 1 is mounted in the player mounting position of the carin parallel with the horizontal plane H of the car, the principal part 2of the player is held by the suspension coiled springs 10 and thecorrecting coiled spring 17 and the dampers 11 is in the neutralequilibrium position as shown in FIG. 3. Therefore, no force istransmitted from the movable chassis 2a to the dampers 11.

If the frame 1 is mounted in the player mounting position at a givenangle with the horizontal plane H of the car with adjusting the coiledspring 17 of the mounting state correction mechanism 12, the directionof gravity of the principal part 2 of the player acting on the bottomsurface of the movable chassis 2a changes, so that the force from themovable chassis 2a is transmitted to the dampers 11 and then, thedampers 11 deform as shown in FIG. 10. Thus, the movable chassis 2adeviates from the neutral equilibrium position with respect to the frame1.

Therefore, if the eccentric cam 18 is turned with the screwdriver (notshown) inserted through the adjustment operation opening 33 so as tooperate the mounting state correction mechanism 12 shown in FIG. 7, theeccentric cam 18 and the rectangular frame 13 are moved from theposition inicated in the solid lines to the position indicated inchain-dotted lines in FIG. 7, and thereby, the biasing force of thecoiled spring 17 increases and the movable chassis 2a is moved from theposition indicated in solid lines to the position indicated inchain-dotted lines in FIG. 7. Therefore, by means of properly adjustingthe angular displacement of the eccentric cam 18 of the mounting statecorection mechanism 12, it is easy to return the movable chassis 2a fromthe position shown in FIG. 10 to the neutral equilibrium position shownin FIG. 11.

FIGS. 12 and 13 show another embodiment of the mounting state correctionmechanism 12 shown in FIG. 1. In this embodiment, one end of the coiledspring 17 is hooked in one of a plurality of engaging holes 34 formed ina line in the connecting member 8 of the frame 1. By selectively hookingone end of the coiled spring 17 in one of the engaging holes 34, thebiasing force of the coiled spring 17 can be changed like the mechanismillustrated in FIGS. 7 and 8.

If the arrangements shown in FIGS. 12 and 7 are compared, it is apparentthat the mounting state correction mechanism 12 shown in FIGS. 12 and 13is not only simpler in construction than the one shown in FIGS. 1 to 11,but also has the coiled spring 17 the capable of being changed largerthan that of the mechanism 12 shown in FIGS. 1 to 11. Therefore, themounting state correction mechanism 12 shown in FIGS. 12 and 13 is moresuitable for the optical disk player for cars which is mounted in theplayer mounting position sometimes in parallel with and sometimes at agiven angle with the horizontal plane of the car.

The present invention is exemplified by the above embodiments. However,various changes and modifications may be made without departing from thespirit and scope of the invention. For example, in the embodiment shownin FIGS. 12 and 13, the end of the coiled spring 17 may be engaged withthe intermediate one of three or more engaging holes 34 arranged in aline at the time when the frame 1 is mounted at a given angle with thehorizontal plane and the biasing force of the coiled spring 17 properlyacts on the movable chassis 2a so as to hold the movable chassis 2a inthe neutral equilibrium position. Thus, if the frame 1 is mounted in theplayer mounting position at an angle which is in a reverse relation withthe angle shown in FIG. 10, and the movable chassis 2a is displaced fromthe neutral equilibrium position not in the direction shown in FIG. 10but in the reverse direction, the adjustment can be performed by meansof having the one end of the coiled spring 17 engaged the engaging hole34 not far from, as shown in FIG. 12, but near to the upper plate 9 ofthe movable chassis 2a. With this adjustment, the biasing force of thecoiled spring 17 is decreased, so that the movable chassis 2a is movedfrom the position indicated in chain-dotted lines to the positionindicated in solid lines in FIG. 12 with respect to the frame 1.Therefore, the positional deviation of the movable chassis 2a from theneutral equilibrium position with respect to the frame 1, which is inthe reverse relation with the displacement shown in FIG. 10, can becorrected. And it is apparent that the operation reverse to thatmentioned above will be enough to correct the position of the movablechassis 2a when the frame 1 is inclined further to the same side as thatshown in FIG. 10. In other words, the correcting operation can beperformed with only one mounting state correction mechanism 12, even ifthe frame 1 is mounted in the player mounting position sometimes at thenormal angle with and sometimes at the reverse angle with the horizontalplane of the car.

Industrial Applicability

According to the present invention, a movable chassis mounted with anoptical pickup, a turntable and the like is supported with a pluralityof coiled springs which are joined with the respective positions of aframe, and at the same time, connected with the frame by a plurality ofdampers so as to absorb the energy of vibrations of the movable chassis.Therefore, the slope of Q-value of the resonance region becomes small atthe leading edge of the slope as compared with the conventional opticaldisk player only supported with rubber cushions, and the vibrationisolation characteristic is improved, so that sound omissions tend notto occur.

Furthermore, even if the optical disk player is mounted at any anglewith the horizontal plane of the car, the principal part of the player,(that is, the movable chassis mounted with an optical pickup, aturntable and the like) can be always kept in the neutral equilibriumposition, so that degradation of the vibration isolation characteristicof the dampers can be effectively prevented, and in addition, thecollision between the frame and the movable chassis can be preventedwithout increasing the movable range of the movable chassis with respectto the frame.

We claim:
 1. An optical disk player in which a movable chassis membermounted with an optical pickup, a turntable and the like, is supportedby a plurality of springs connected to respective positions on a framemember to hold the movable chassis in a floating state with respect tothe frame, comprising at least one damper inserted between said framemember and said movable chassis member so as to absorb the energy ofvibrations of said movable chassis, each said damper comprising agenerally horizontal rod fixed to one of said members and a resilientvessel of viscous liquid secured to the other of said members with saidrod secured centrally of said vessel, and correcting means between saidmember and said movable chassis member to adjust a resilient biasingforce for biasing said movable chassis with respect to said frame byadjustment operation, wherein a positional deviation of said movablechassis causing movement of said rod away from centered condition insaid vessel is corrected by adjusting the biasing force, so that saidmovable chassis is kept with said rod in centered condition in neutralequilibrium position regardless of the setting angle of said frame. 2.The optical disk player according to claim 1, characterized in that saidmovable chassis is suspended from said frame by said springs, and foursubstantially spaced dampers are provided.
 3. The optical disk playeraccording to claim 1, characterized in that said frame comprises a pairof side plates and a connecting member by which said pair of side platesare connected with each other, said connecting member being providedwith adjusting means for changing the biasing force at an angle to thehorizontal.
 4. The optical disk player according to claim 3,characterized in that said correcting means is a coiled spring securedbetween said frame and said connecting member.
 5. The optical diskplayer according to claim 1, characterized in that said adjusting meansis an eccentric cam.
 6. The optical disk player according to claim 1,characterized in that said frame is accommodated in a cabinet, in theupper wall of which an opening for adjustment operation is formed inorder to operate said adjusting means.
 7. The optical disk playeraccording to claim 1, characterized in that said vessel comprises anelastic material, enclosing a viscous fluid in a space defined withinsaid vessel, and said rod being coupled to said vessel, said vesselbeing provided with a prism-like portion projected into said space andsecured to said rod for movement therewith and for resisting movement ofsaid rod relative to said vessel to thereby increase energy absorptionupon relative movement of said rod and said vessel.